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HomeMy WebLinkAboutCT 98-14; Thompson/Tabata; Tentative Map (CT) (140)CONSULTING October 10, 2002 JN 10-102194 Mr. Clyde Wickham City of Carlsbad 1635 Faraday Avenue Carlsbad, CA 92009^*387 Subject: Response to Substantial Conformance Exhibit Plan Check Comments, Carlsbad Tract 98-14 Dear Mr. Wickham: We have completed our review of plan check comments for City of Carlsbad Tract No. CT98-14, Substantial Conforming Exhibit, and have addressed the comments as requested. Sheet 3 of 8 Comment: Response: Sheet 3 of 8 Comment: We have a question/concern as to why you are raising lot 226 from elevation 304.5 to 309.1 (an increase of 4.6). The street appears to be at 304 and the increase will cause steep driveway problems as well as additional slope issues. This is the area where you have reported to be short on dirt because of a large trash deposit and a 50,000 cubic yards haul off to the dump. Simply put, raising pads requires additional dirt that you don't have. The same comment applies to lots 227 and 228. Lemon Leaf was raised from the approved Tentative Tract Map to eliminate the need to remove existing improvements. If the vertical elevation and street grades are used as approved, it would be necessary to remove a portion of the existing street and thus impact adjacent home owners. By raising the road vertically, we are able to match the existing street without impacting the existing improvements. The previous plan should have indicated the revised street grades along with the required pad changes. However, the street vertical adjustment was inadvertently left off. This error has been corrected. The proposed change to lot 229 is incredible. You are proposing to push the existing 20' slope offsite, beyond the boundary of the subdivision. The benefit to the lot is evident by an increase of almost a 50' backyard. The proposed offsite grading includes a new desiltation basin adjacent to Aviara Parkway with an outfall to the south where we have a serious concern about increasing runoff and have conditioned this project with erosion protection. Your engineer has tried (and currently proposes to leave the outfall in its present condition). At this time, we object to the proposed changes to Area 1 other than minor pad elevations relating directly to Lemon Leaf at the existing connection. PLANNING a DESIGN 9 CONSTRUCTION 14725 Alton Parkway, Irvine, CA 92618-2027 • P.O. Box 57057, Irvine, CA 92619-7057 • 949.472.3505 • Fax 949.472.8373 Offices located throughout California, Arizona & Nevada • www.RBF.com printed on recycled paper Mr. Clyde Wickham October 10,2002 Page 2 JN: 10-102194 Response: The slope on the backside of lot 229 has been revised to more closely reflect the approved Tentative Map, while including a depressed area that can be utilized as a storm water detention basin. These changes are a direct result of the city's concern for a method to reduce any additional runoff and the resolutions derived from the Substantial Conformance meeting held on September 17, 2002. Sheet 4 of 8 Comment: Response: Sheet 4 of 8 Comment: The proposed changes to these sheets appear to be driven by the shortage of dirt from Area 1 and from a bust in elevation used to design this project Overall we do not object to the decrease in pads but would like to see them reduced in size (instead of a 3' decrease use a 2' decrease). This statement applies to Lots 1 through 59. The pads elevations on the interior lots will remain at the 3' decrease; however, the exterior and visible lots have been revised to show a 2' decrease. These changes are a result of the resolutions derived at the Substantial Conformance meeting held on September 17,2002. The proposed change to the storm drain in Poinsettia Lane needs to include calculations for capacity of adding and 18" storm drain to a 24" storm drain with non-pressure flow. The outlet volume as well as velocity will probably exceed the capacity of the existing brow ditch and as proposed, is not supported. We have specifically conditioned this project to install an energy dissipator at this outfall (ref. Sheet 4 D-41 Energy Dissipator") We cannot support the deletion of this feature in light of adding more drainage to the same system. Response: The storm drain will remain as shown on the Approved Tentative Tract Map. This includes the Energy Dissipator. Sheet 4 of 8 Comment Response: We believe there is a mistake at the intersection of "A" Street and "I" Street. The change from elevation 251.1 to 258.5 and also from 251.5 to 258.5 is wrong. There would be a 7' bump in the intersection. We have revised the plan to reflect the correct elevations. These are 248.1 and 248.5 respectively. Mr. Clyde Wickham October 10,2002 Page 3 JN: 10-102194 Sheet 5 of 8 Comment: Response: Sheet 5 of 8 Comment: Response: Sheet 6 of 8 Comment: Response: The proposed 15' wall for lot 166 is not supported. This change would require additional discretionary review. We have revised the plan to show 2 retaining walls. This revision is in direct response to the city's wishes and the resolutions derived at the Substantial Confbrmance meeting held on September 17,2002 The proposed wall for lot 152 is not supported. We have removed this retaining wall. The proposed changes to lots 205 through 224 seem to be a separate issue but would require more dirt. That could be better used to fill the reported 50,000 cubic yards hole created to the east (area 1). Using this earthwork instead of raising pads could reduce the amount of cut on other portions of this project as well as the amount of trucks crossing City roadways. The area of requested changes is also an area where we have received comments from Mr. Harrington, an attorney for Nobe Tabatta. A concern of Mr. Tabatta's sewer leach field or a percolated seepage issue should be investigated before requesting changes to an approved plan. Additionally the area of proposed revision has also been an area where the adjacent Condominium owners have voiced concern regarding sewer, storm drain access, and grading of their trees. Stepping these pads up an additional 3 feet along their project could exacerbate their concern and complaints. The proposed retaining walls and lot line modification are not clear. We would like to discuss the proposed changes in terms of your adjacent neighbors (Tabatta and Briarwood) and the impacts to them before a decision can be made. Any information in the form of a soils report of Geotechnical report on the slope/ sewage issue would also help. We have revised the plan to reflect the resolutions derived at the Substantial Conformance meeting held on September 17, 2002. The pads along the east side of Lonicera have remained raised. This is in direct response to Nobe Tabbatta's request to be compatible with his future development. Additionally, we have lowered the pads along the West side of Lonicera to accommodate the request of the adjacent Condominium owners. The Sewer leach field is a separate issue. This is a problem that must be resolved prior to Rough Grading but is not a direct result of any changes made on the Substantial Conformance exhibit. Mr. Clyde Wickham October 10,2002 Page 4 JN: 10-102194 Sheet 7 of 8 Comment: The proposed Lot Line Adjustment for lots 197,198,198,199, 200 & 201 is not acceptable. Response: We have revised this Lot Line to reflect the Approved Tentative Tract Map. Sheet 7 of 8 Comment: Response: Sheet 3/6 of 8 Comment: Response: The proposed 6' MSE retaining wall adjacent to lot 67 in not approved. It was a resolution of the Substantial Conformance meeting held on September 17,2002 that this MSE retaining wall would be allowed. Revise fire hydrants spacing of Lemon Leaf and Lonicera to 500' spacing. (City of Carlsbad Fire Department) Martin Aguilera of the City Fire Department was contacted to discuss his concern about hydrant spacing along Lemon Leaf and Lonicera. He indicted that 300' spacing currently shown on the plans is acceptable. These responses to comments are returned for your review and approval. Please feel free to call me at (949) 472-3405 with any questions. Sincerely, 1^£^ Tom Mitchell, P.E. Land Development TM:glw:H:\pdata\10102194\Admin\letters\subconfbrming-comments-2.doc